Question

Why does itertools.permutations() return a list of characters or digits for each permutation, instead of just returning a string?

For example:

>>> print([x for x in itertools.permutations('1234')])
>>> [('1', '2', '3', '4'), ('1', '2', '4', '3'), ('1', '3', '2', '4') ... ]

Why doesn’t it return this?

>>> ['1234', '1243', '1324' ... ]

Answer 1

itertools.permutations() simply works this way. It takes an arbitrary iterable as an argument, and always returns an iterator yielding tuples. It doesn’t (and shouldn’t) special-case strings. To get a list of strings, you can always join the tuples yourself:

list(map("".join, itertools.permutations('1234')))